The Fischer-Tropsch process is used primarily to convert carbon monoxide and hydrogen, also known as “syngas”, into liquid hydrocarbons for use as fuel.
A typical process flow diagram where a Fisher-Tropsch process is used to synthesize hydrocarbons is as follows:

In the above process gasifier feedstocks are usually coal or methane gas. In this diagram Q1 represents the energy input into the gasification (in the case of a coal feedstock) or reforming section (in the case of a methane gas) and Q2 represents the energy output from the Fischer-Tropsch synthesis process.
Where coal is used as the feedstock it is, initially, converted to carbon monoxide (CO) and hydrogen gas (H2) by the following gasification process:C+H2O→CO+H2 
The carbon monoxide is then partially converted to carbon dioxide (CO2) and hydrogen (H2) by the following water gas shift process:CO+H2O→CO2+H2 
The water gas shift process is controlled so as to provide the required CO:H2 molar ratio for the Fischer-Tropsch process. Typically the CO:H2 molar gas ratio is 1:2. The CO2 produced in this way is emitted by the process and leads to carbon inefficiencies.
Where methane (CH4) is used as the feed the reforming process is used:CH4+H2O→CO+3H2 
As in the case of the coal fed process the water gas shift process partially converts the carbon monoxide to carbon dioxide so as to provide the required CO:H2 molar ratio of 1:2 for the Fischer-Tropsch process. The carbon dioxide created in this way is emitted by the process.
As indicated above, the CO and H2 gas combination is termed “syngas” and it can be used in the Fischer-Tropsch process to produce a wide range of carbon based chemicals perhaps the most important of which is fuel for internal combustion engines.
Syngas production processes are endothermic and, consequently, require considerable quantities of energy. This, also results in the emission of significant quantities of carbon dioxide which, because it is a so-called “greenhouse gas”, militates against the above-described synthetic fuel plants. On the other hand, dwindling and increasingly expensive crude oil stocks, coupled with significantly large resources of natural gas and low grade coal, militate for the erection and operation of such plants.
It should be noted that the following terms, when used in this specification, have the following meanings:    1. By “carbon efficiency”, it is meant the amount of carbon in all the feeds to the process (including all feed streams that provide energy) that occurs as carbon in the desired product; and    2. A “CO2 rich syngas” is a gas mixture in which there is CO2, H2 and CO. The CO2 composition in this mixture is in excess of the CO2 which would usually occur in conventional syngas. The CO2 is utilized as a reactant and is converted into the desired product.